Tunneling Magnetoresistance In Silicene Spin Valve Structure

In this paper, we investigat the conductance of normal/ferromagnetic/normal/ferromagn- etic/normal silicene structure, when the magnetization configuration of the ferromagnetic silicene is parallel or antiparallel. The mathematic method we used is the transfer matrix. Then we calculet the tunneling magnetoresistance based on the result of conductance.Firstly, we research the valley conductance, charge conductance and valley polarization conductance as a function of Fermi energy when the magnetization configuration of the ferromagnetic silicene is parallel. With the same method, we also calculate the conductance as a function of the length of normal and ferromagnetic silicene. The result shows that, the conductance of K and K’ valley are oscillatorily raise with the increase of Fermi energy, while as a function of the length of ferromagnetic, it first increases and then oscillates, when me VZ=Δ7.11 there will be completely polarized valley phenomenon, and the conductance of K and K’ valley is quasi-periodic oscillating as a function of the length of normal silicene. Secondly we investigate the valley conductance, charge conductance and valley polarization conductance as a function of Fermi energy, the length of normal silicene and the length of ferromagnetic silicene under the condition of magnetization configuration of the ferromagnetic silicene is antiparellel. In this case, due to the particular combination of the direction of magnetization with valley and spin, the value of conductance about K valley and K’ valley is completely equal, then the conductance is unpolarized. The tendency of conductance for either the ferromagnetic region of the silicene junction is parallel or antiparellel can get a reasonable explanation based on the energy band digram of the silicene junction.Finaly, we investigate the tunneling magnetoresistance(TMR) in silicene junction structure. We find that the TMR was constantly oscillating with the increase of the length of ferromagnetic silicone under certain parameter in the studied silicene junction. When me VZ=Δ7.11 with the increase of the length of ferromagnetic silicene the value of TMR first oscillate, then maintaine 100%. Regardless of the value of ZΔ, the TMR is quasi-periodic oscillate with the increase of the length of the normal silicene. If the ZΔ is become larger, the overall value of the magnetic resistance will increase.